Castellani’s use of aluminium in the production of this piece indicates how prized the metal was at the time. It was discovered in 1827 but extraction was incredibly expensive, until H. Saint-Claire Deville developed a process for producing aluminium industrially in 1854. This had a swift effect on the metal’s cost, falling from 3,000 francs per kilogramme in 1855 to 375 francs per kilogramme a year later.
For a similar example see Munn, G.C. Castellani and Giuliano, London, 1984, p164 plate 72